基于DSMC方法的高空固发羽流模拟

Simulation of High Altitude Solid Rocket Plume Based on DSMC Method

为研究稀薄状态下固体火箭发动机羽流中颗粒的行为,在稀薄气相流场DSMC程序的基础上,添加了气固两相相互作用模型和颗粒相变模型。气固两相相互作用模型中,颗粒所受的作用由单个颗粒受到周围分子力和热作用公式求出,分子所受的作用由耦合求解气固相互作用方法求出,颗粒相变考虑固化、熔解,以及不发生相变的加热与冷却。用算例研究了流场的特性参数及不同粒径颗粒的温度分布,与文献数据符合良好,准确度在国内同类研究中具有一定的优势。在此基础上,针对实际固发羽流算例进行计算,分析了不同颗粒直径对流场的影响。结果表明:粒径越小颗粒扩散越开,X=0.4 m处粒径1μm颗粒的扩散较粒径100μm从0.03 m增大到0.2m;粒径越小颗粒温度降低越多,X=0.4 m处近轴线位置粒径1μm颗粒的温度较粒径100μm降低了44.4%;粒径越大,对气相流场阻碍作用越明显,X=0.02m处近轴线位置粒径100μm颗粒的速度较纯气相流场降低了54.5%。

In order to study the behavior of particles in the solid plume in the rarefied state,the gas-solid twophase interaction model and the particle phase transition model were added on the basis of DSMC program.In the gas-solid two-phase interaction model,the force and heat of the particles are obtained by using force and thermal effects of single particle subject to the surrounding molecular.The force and heat of the molecules are obtained by the method in the technical route for solving gas-solid interaction.The particle phase change is based on the model which includes solidification,liquating and heating and cooling without phase change.The characteristic parameters of the flow field and the temperature distribution of particles with different particle sizes were studied by one sample.The results were in good agreement with the literature data.The accuracy of the results in the same research in domestic has certain advantages.The calculation of a real solid-rocket plume was carried out,and the effect of different particle diameters on the flow field was analyzed.The results show that the smaller the particle size,the more the particles diffuse.The diffusion of particles with diameter 1μm is changed from 0.03 mto 0.2 m at X=0.4 mcompared with particles with diameter 100μm.The smaller the particle size,the more the particle temperature decreased.The temperature of particles with diameter 1μm is decreased by 44.4% at X=0.4 mnearaxis position compared with particles with diameter 100 μm.The larger the particle size,the more obvious obstruction of molecular motion in the flow field.The molecular X velocity is decreased by 54.5% at X=0.02 m near-axis position compared with the pure gas flow field.